Laser scanners of the type specified above are commercially available, e.g. under the trade name “iQsun 625” from the assignee of the present application.
Laser scanners can be used for scanning closed or open spaces like interior spaces of buildings, industrial installations, tunnels and the like. The rotary mirror, rotating at high speed about a horizontal axis, generates a fan of light beams in a vertical plane. This fan of light beams, in one type of 3D laser scanners, is in turn rotated about a vertical axis through the entire surrounding space with a much slower rotational speed. In other types of 3D laser scanners the fan of light beams is not rotated but displaced along a given trajectory, for example on board of a wagon moving through a tunnel.
The light reflected by objects within the space surrounding the laser scanner is received by the laser scanner and is processed. When doing so, the reflectivity as well as the distance for any measured point is determined. Seen as a whole, the laser scanner thereby generates a true 3D image of the space surrounding the laser scanner with 360.degree. spatial angle under ideal conditions or along a given trajectory.
Such laser scanners are relatively complicated and sophisticated instruments and, hence, accordingly expensive. On the other hand, in practice such laser scanners are distinctly configured for distinct operational and measuring requirements, wherein the decisive criteria are the precision of the measuring results, the spatial measuring range and, finally, the particular rotating mirror design.
If a user, for cost reasons, makes a decision for a specific type of a laser scanner being in the lower range of these criteria, then he/she is bound to this class of specifications. This means that the user, in case that at a later stage a scanner of a higher class of specifications is required, and the user is willing to make an accordingly higher investment, an entirely new instrument must be purchased even if the higher requirements concern only a few of the laser scanner components.
Moreover, in case of a malfunction of the laser scanner, the entire instrument is down and must be serviced. Considering that there exist only a few specialized manufacturers of such laser scanners worldwide, such service or repair may require shipping the instrument over long distances.
It shall become possible to provide a laser scanner with which a user may step from one class of specifications to another class without the necessity to purchase an entirely new instrument. Further, it shall be possible to reduce the down time of a defective laser scanner to a minimum.